feat(privacy): add --format json, --output flags and summary to scan results (#31)

[shabbirAlam]

Fixes #31
Problem
greenlight privacy /path --format json failed with Error: unknown flag: --format, while codescan, preflight and playscan all support --format json / --output. Privacy JSON output also lacked the summary object (total, critical, high, warns, infos, files_scanned, passed) present in other scanners.
Solution
Bring privacy to parity with other commands.

Verification
make build

1. JSON to stdout (now works)

./build/greenlight privacy /path/to/project --format json

2. JSON to file

./build/greenlight privacy /path/to/project --format json --output report.json
cat report.json # contains summary + elapsed

3. Terminal unchanged (default)

./build/greenlight privacy /path/to/project

4. Tests

make test # all pass
Example output (--format json):
{
"project_path": "/path/to/project",
"has_privacy_info": false,
"detected_apis": ["User Defaults"],
"summary": {
"total": 2,
"critical": 2,
"high": 0,
"warns": 0,
"infos": 0,
"files_scanned": 0,
"passed": false
},
"elapsed": "290ms"
}
Checklist

• Follows existing patterns in internal/cli/codescan.go:56 and internal/cli/playscan.go:64
• Summary JSON tags match codescan.Summary
• No breaking change to terminal output
• make test passes

---

Note

Low Risk
CLI-only reporting changes with default terminal behavior preserved; no auth or data-path changes.

Overview
Brings greenlight privacy in line with codescan, preflight, and playscan by adding --format (terminal default, json) and --output to write reports to a file instead of stdout.

JSON mode skips the colored banner, emits an indented payload that embeds the scan result plus elapsed, and includes a new summary block (counts by severity, files_scanned, passed) computed at the end of privacy.Scan. Terminal rendering is unchanged in content but now writes through a shared io.Writer so the same report can go to stdout or a file.

^{Reviewed by Cursor Bugbot for commit 9579d82. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

Want higher recall? High effort reviews run extra passes and find more bugs. A team admin can switch effort levels in the Cursor dashboard.

^{Reviewed by Cursor Bugbot for commit d3d9af5. Configure here.}